Cisco CCNA mock exam questions sample test – Question 174

.Which of the following excerpts from the output of the show ip eigrp topology command include EIGRP learned routes or pairs of routes that will be included in the routing table? (For
excerpts that include multiple routes, do not include the entry unless BOTH routes will be included in the routing table.)

A. P 172.16.16.0/24, 1 successors, FD is 284244
via 172.16.250.2 (284244/17669856), Serial0/0
via 172.16.251.2 (12738176/27819002), Serial0/1
B. P 172.16.250.0/24, 1 successors, FD is 2248564
via Connected, Serial0/0
C. P 172.16.10.0/24 2 successors, FD is 284244
via 172.16.50.1 (284244/17669856), Serial1/0
via 172.16.60.1 (284244/17669856), Serial1/1
D. P 172.16.60.0/24, 1 successors, FD is 2248564
via Connected, Serial1/1

Correct Answer: C

Explanation:
The following excerpt indicates two successor routes, and they will both be included:
P 172.16.10.0/24 2 successors, FD is 284244
via 172.16.50.1 (284244/17669856), Serial1/0
via 172.16.60.1 (284244/17669856), Serial1/1
Both of these routes will be included because they have identical metrics (284244/17669856). Only the EIGRP successor routes will appear in the routing table, as these are
considered the best-path routes to each remote network.
The route for 172.16.16.0/24 via 172.16.251.2 (12738176/27819002) will not be included because only successor routes are included, and this route is a feasible successor. Feasible
successor routes are routes that are used only as a backup if the successor route(s) becomes unavailable. If you examine the output of each option, it will indicate how many
successor routes are in the entry. The entry shows that there is only one successor to this route:
P 172.16.16.0/24, 1 successors, FD is 284244
via 172.16.250.2 (284244/17669856), Serial0/0
via 172.16.251.2 (12738176/27819002), Serial0/1
The first listed is the successor and the second is the feasible successor. The first has the best or lowest metric (284244/17669856), which is the criterion used for selection.
These entries indicate successor routes, but they also indicate they are via Connected, which means they are networks directly connected to the router.
P 172.16.250.0/24, 1 successors, FD is 2248564
via Connected, Serial0/0
and
P 172.16.60.0/24, 1 successors, FD is 2248564
via Connected, Serial1/1
Therefore, they are not EIGRP learned routes.
Objective:
Routing Fundamentals
Sub-Objective:
Configure, verify, and troubleshoot EIGRP for IPv4 (excluding authentication, filtering, manual summarization, redistribution, stub)
References:
Cisco > Cisco IOS IP Routing Protocols Command Reference > EIGRP Commands: M through V > show ip eigrp topology